In washrooms, it is common to provide one or more sinks or water basins for washing, and one or more separate, wall-mounted hand-dryers which users can then use to dry their hands.
FIG. 1 illustrates one type of wall-mounted hand-dryer 1, which is currently marketed and sold under the model name AB01, as part of the Dyson Airblade® range of hand dryers. It works by using a motor-driven fan to force air at high pressure through an opposing pair of narrow, slit-like nozzles 2, 3, each less than 1 mm wide. This creates two opposing thin sheets, or “blades”, of high velocity air which act to strip water from the front and backs of a user's hands as they are ‘dipped’—palms flat—between the opposing nozzles 2, 3.
The drying air is fed to the nozzle 3 via a respective air duct 3a which connects to the pressure side of a motor-driven fan (not shown) located inside the hand dryer 1. The air duct 3a flattens near the nozzle so that it spans the width of the nozzle 3. Consequently, air is fed from behind the nozzles 3, with different portions of the nozzle 3 effectively being fed in parallel, and the air exits the nozzle 3 “straight-on”. This is illustrated in FIG. 1.
Air is fed to the rear nozzle 2 in a similar manner via a separate duct (not shown) corresponding to the duct 3a. The nozzle 2 is scalloped to follow the back of the user's hands: this deliberate physical shaping of the rear nozzle encourages “turning” of the airflow as it passes through the nozzle 2, so that air is angled both into the thumb and forefinger of the user and also back into the little finger of the user, which improves the overall drying performance. This is also illustrated in FIG. 1.
In some washrooms, hand dryers are instead located over the basin of the sink, so that a user can conveniently dry their hands at the sink—without having to move—and at the same time water dripping from the hands can collect in the basin of the sink and drain into the mains drainage system through the existing waste pipe. One such arrangement is described in U.S. Pat. No. 5,199,118A.